Telephone-exchange system.



L D. KELLOGG IELEPHQNE EXCHANGE SYSTEM.

APPUCAHON mu) NOV. 2?, 1905.

1.2041783. r Patented Nov. 14, 1916.

il M m/uw j wwwtmr Cwiggg, My 0.

L. D. KELLOGG.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FIL ED NOV. 2-, I896.

SSHEEIS SHEH 2.

Patented Nov. H, 1916.

L. D. KELLUGG TELEPHONE EXCHANGE SYSTEM.

APPLICATION HLED NOV 27.1906. 1

Patented Nov. 14, 1910.

3 SHEklS-SHEET 3.

ling

nect on mey he completed, and that systems rnrnrnour excnenos srsrnm.

Specification of Letters Patent.

Uurr'eo srn rns PATEN current LEE-CY D. KELLOGG, OF CHICAGO, ILLINQ IS; ASSIGNOR, BY MES NE ASSIGNMENTS, '10

KELLOGGSWITCHBOARD dz, SUPPLY COMPANY, A CORPORATION OF ILDINOIS.

Patented NOV.'1at, 191 5.

Application, filed November 27, 1906. Serial No; 845,290.

zelt'of the United States, residinglpt Chicagmin the county ofCook and State?- of 1llin is,-have invented new and useful improvements in Telephone-Exchange Sysreins, of which the following isa specificaliltlll.

M invention relates to telephone systems wherein ,trunk or link-circuits are employed, adapted to be used for putting through the connections of a plum ity of telephone circuits by the aid of electrically controlled or adjusted. selective switching mechanisms associated with said links, an ohjeetof my invention being to provide a structure wherein the said switching mechauism of a link or trunk maybe indifl'ercutly employed for incoming and outgoing calls of the telephone circuits which the trunk may serve.

A; feature of the invention consists in this that the same selective switch may bets-n1- ployejd to*extend a circuit served byit to desired point, or may be employed to BX- tend connection from another point to a circuit served by it.

I have elected to show my invention applied to a. system wherein a pluralityl of selective switches common to a plurality of lines, are employed to automatically connect the central office link-circuits 'operetively with calling lines and wherein the same switches are employed, to automatically extend the circuit of the callingjline to the called line.

In accordance with the application of my invention herein shown, I provides number of twitches common to a. group of lines and so arrange their circuits and mechanis'm' that each-onemaybe employed for either oftheabov'e' indicated purposes; that is to say, for a group oi one hundred lines, for instance, ten such switches may be provided und'each one is indifl'erently available, .plac'd in use and' sorendered busy, utgoing or incoming collect the hues e; roiipl I am aware that it has hereeen' Iproposedto' employ switches to ufplurality of circuits for autoconuecting a link-circuit to a call it which link-circuit the conh-a'ife also Jpeen proposed wherein selective "'c hsracteristic-s.

switches were to be employed to connect with culled circuits, and that systems have been proposed including both of the above I am, however, not aware of any prior system wherein a selective switch is provided capable of use in either direction or capacity interchangeable.

Referring to the drawings Figures 1 and 2, illustrate diagrammatically circuits of a telephone system embodying an application A of my invention. .Figs. 3 and i show re spectively top and side news of a musterswitch. Figs. 5 and 6 are similar views of a selective switch employed in connections with'the circuits. i i

In accordance with the embodiment of my iuventiol'i shown, I provide for a group of lines, say fifty or one hundred, a number of selective switches proportioned in number to the number of co-ciisting calls to be expected from and to the lines of the group at the busiest time. lhcseswitches serve the lines (us cullinglines; to automatically connect to them circuits over which the connections may be completed. They are preferably not constantly operating devices, but remain at rest until a signal is sent over a calling line, whereupon a distributing device causes an idle switch to start its oper-- ation which then uutou'iatically continues until the switch hus sought out and found a calling line. (.lmwersely the switches serve the lines of the group to which they are assigned, as called lines, to complete cir' cuits from lines of the same or other groups to them as such called lines. It is, of course;

essential in such an arrangement that as soon as a switch is put in use for either purpose it be rendered unavailable for other use in either capacity until released atthe proper time amd to that end, I arrange the structure so that abusv potential or indication is placed upon a l circuits of a busy switch by which it may in it's normal condition be influenoeda It is obvious that my invention will render any system to which may he applied, extremely flexible incharacter inasmuch as a fixed percentage of switches assigned to any group of circuits will enable a numbecof outgoing calls totaling the number of switches to co-exist from the group or the I in calls may be in any proportion, limited on y by the number of switches.

It is not my intention to limit the claims in such manner that they will not cover my invention in connection with purely auto matic telephone s stems, in which it.may obviously'be emp oyed, although the particular application 1 herein; show includes a system nu which certain portions of the connections are completed by the aid of central ollice operators.

In Figs. 1 and 2, I show an application of my invention to the supplying of service resembling to a certain extent lockout party line service. In the system therein shown each of-a group of, say, fifty subscribers has his individual substation and a. short line extending therefrom to a. location wherein are placed a plurality of selective switches, say live or ten. Each line may there terminate in passive multiple contacts appearing in the banks and being adapted to be engaged by each of said switches.- As suming tivc switches to be provided, five trunk lines, each individual to a switch would be provided extending to a central ofiice where they may terminate in ;an ariswering jack, with an associated signal, and multiple jacks. A subscriber making a call will by the removal of his receiverialter the electrical condition of his individual short line'to cause a switch to connect his trunk line to the short line; the em'diungesignal of that trunk line will be displayed and the operator will answer as in usual manual practice by inserting an answering plug in the answering jack associated with the signal, learn the number wanted and complete the connection by inserting the calling plug belonging to the answering plug used, after making the usual busy test, into a multiple sprin jack having connections suitable for completing the call. This multiple spring jack maybe a terminal individual to a subscribers line or it may be a terminal pertaining to a trunk line leading to a selective switch of the character hereinbefore described, belonging to the same group of lines among which the calling line is included or belonging to another similar group. In case such trunk or link-circuit is used, the operator will employ her calling device, of which one may be provid d per position with keys for connecting it c any cord at the position, to transmit directive ,curreuts to the trunk switch to adjust it to connection with the particular line wanted,

'when the switch will automatically test the called line and if the some he found busy, the switch will be automatically restored to normal and a busy signal extended to the calling subscriber or operator. I provide the usual supervisory signaling apparatus, one signal bein controlled by each sub scriber and pre erably organize the system together.

in such manner'that after connection has once been completed between two lines, the

restoration of the selective sjvllitcll is 0 controlled by the ope rat: r.

My invention will be more particularly described in connection with the accompanying drawings, but it will be understood that the invention is not limited to the particular application and instrumentalities in associationwith which I have elected to illustrate and describe it.

'(Jlencrally stated, an exchange organized to employ the arrangements shown in Figs. 1 and 2 may comprise a group1 or a plurality of groups of lines such as but of A, cool group having its master-switch K,one for the group, and a plurality of selective switches C common to the roupl The switches of a group are prefera ly placed at a location as close as possible to the substations in order that the individuallincsL Iflmn be as short as possible while the trunk linefi her only a small percenta of the individual lines, form the long linksgiving access to the exchange. The multiple spring ]a' f of the trunks may appear at each sectioljlf the usual multiple switchboard along with the multiple jacks of ordinary subscribers lines such as that of F. The multiple trunk jacks of a group of switches are preferably mounted in the multiple jack frame adjacent to one another in order that an operator making the usual test to find an idle trunk of the group may have them all close The. call lamps and answering jacks of the trunks belonging to a particular group of subscribers may all be placed at one operators position or may be distributed among several'operators.

Referring more' specifically to Figs. 1 and 2, as shown at A, a subscribers substation equipment includes the usual transmitter, receiver, condenser and bell with book lever 1 normally closin the bell circuit, and adapted, on removal 0 said circuit, and connect thetransmitter and receiver operat ively line is provided at the exchange with the line relayv 2, adapted, the substation, to operate the mastexj-switch mechanism K to start an idle selective sivitch L',innum- .the receiver to openwhen a call is initiated at 1 with the line. The said G in search of the eallin line. The line is also provided with multip e contacts 14--16-- associated multiple spring ja'ccs.

provided with signal relay 47 with its associated lamp 50 and cut-elf relay l l and the As soon as switch (3 isstarted, signal lamp zilis-displayed and a busy test placed upon the test contuctsbl. of the multiple jacks. The operator answers the callhy inserting the unswering plug G of her cord circuit E into the answering spring jack directly associated with the signal lamp, itbeingunderstood,

that tho multiples of said spring:jaelea-ppear :it the various sections he multiple snifchhoarcl in the llfillll .in rihein'i The Oberutor Will 'then inquire thejnumber of thesuh- I 'scrihor wanted, and if the line wanted bean individual line such as that of F, the opera-- tor will, after testing the line, insert the calling" plug H of the cord circuit E into a multiple jack of thewantecl line and rings the called subscriber in the usual manner. The replacing by the two connected subscribers of their ,receirers at the conclusion of conversation will display the supervisory signal lamps 64 and 88, and the operator-Grill withdraw the two plugs of the cord circuit, the withdrawal of the answering'plugcaus ing the switch 0 to r'e't urn to normal and be available for further culls. Assuming however, that the line ivanted is splineincluded in the same group as that of A or anyfother sirnilur group; the operator insuch case, by. means of the callmq' plug of the cord circuit,

will test tlieinultiple spi -ing jacks eithe trunks pertaining to the group among which the line of the calledsubscribor is included 'and on finding an-idle jack will insert the calling plug: therein, which aet ivill place 'a busy potential on the testtcontects 51; the operator will then actuate the impulse transmitter 74 to send a number of im plses representing the number of the calle subscriber in his group. The transmission of the first impulse in addition to advancing the selected "switoh' C a step toward "the called line removes said switch from sil con troletercised byth'e masterswitch mechanism K, Vl hen theproper niiunher of unpulses have been transmitted by callihgcde- "rice 74 toplaee wipers.15-17 -1921 upon contacts of the calledline, the said line will be autoniatically tested by theswitch 16 If" the said line he foundbusy, the: selector will be automatically restored to normal and'the operator will-receive a busy signal in her telephone, and willtake down the conned tion in the usu'el manner; Ifthedine he foundjidle, no'husy signal will be received o l i u n and theswitch will, of course, reniain inconnection-with the contacts ofthe called line, the operator then" including the generator in circuit with the-called line-to ri-n' the bell of the cs'lledsubscriberr v'Ihecorc circuit arrangement-shown at It is adapted ior .use in "completing f conn action between two lines of the character'of that shownaat A, ,or.

"attracting its upper armature closes n locktwo lines thecheractcr of that shown at F, orhetween trio lines of the dillerent classes of which either one may he the calling line. 'lo truceuiorc in detail the operation of the mechanism described, let it be assiunod that the subscriber at A desires his line to he connertrd with that of thesubscribernt F, llc removes his receiver from the ho'oh leyer causing the energization of relay 2 by current from battery B. through the said relay, norn al contact of armature c-l, o'rer line liinl'llu'lfl, hoololever 1 returning over liue'lirnb I]? and back contact of upper nr-l mature of relay 3. to ground. Relay 2 in 8O ing circuit-for itself to ground at theuppcr armature of relay '3. The lower armature of relay 2 is attracted to remove the normal ground from the multiple. contacts 18 of the line, and by engaging contact 2 to close cic cuit through relay 6 of the Jl'lilStGl' switch mechanism K, energizing the said relay, which in attracting ts armature, completes a circuit from ground through the backc'oii-J tact of the armatureof relay 9, contacts 10-12; it being assumed that the mastersu'itoh wipers 10-l1 are engaging thecon itacts-19r-.-13 pertaining to-switch C) over conductor 56, normal contact of armature 31, back Contact of armature of may 42 5 through relay 22 to battery. The said rel'a'y 2'2 attractsits armaturesjof which 23 and 28 place line-aripers l5'-17,i p onopen circuit in order that they may not interfere yvjitli conversations existing over, lines whose colioo tacts they'inaiy wipe n theloperation ott'the switch (3.. Armature 27 coinpletes acir'cii'it litonrflround throug h relay 38 over 11ml) L of the trunk circuit to the exchange, through rela y 47 thereat tobuttery B'Qpjr 1 cratingrelay 38 to disconnect polarizedftest relay 39:;Eron1 the alternate contact (if inhture28eiuorder that said relay se m iy not be connected to line wiper 17 while it is wipingorer' busylcontacts. The energized 11o relay 47 attracts the armature 49 to display lamp 50 andarinature 48, to connect battery .to the .test' contacts 51 of: the trunk spring jacks to render them busy. Thus, as soon as switch C has its Starting relay 22operated115 as a'line selector, the trunk jacks are-lien dared-busy In v other Words, the cliahgi'h the normal electrical condition'of the sen multiple terminal-'12, corresponding to the link-circuit, renders busy the multiple jaclc terminalsnqlhe attraction of armeture 'giltg of relay 22 completes a circuit from groiirid througliback contact of armature 30 through operating magnet M, baclrcontact o'i 1hr mature 3,3 and through interru i-ter ,I ito as;

battery B, nl1ile'armature'25 connectsfthel; winding of relay 22 with theprivrit ri" er" v 1.9,- The-interruptor I not transmits clinrent impulsesthrough-magnet M, ear

tuation of said, magnet advancing, he

'wipers a step until the-relay 22 becomes fully explained, the first contact engaged by a wiper 19, when a switch has started to operate, is. permanently connected to ground,

while the firstcontacts engaged by the other wipers 15-17'21, are. open or dead contacts. when with the first actuation of the magnet M, wiper 19 engages the grounded contact, a locking circuit is completed from battery- B through relay 22, back contnctpfarirrature of relay 42, armature 25 and its alternate contact, wiper 19 to ground,'holding relay 22 energized. Magne't M new advances the wipers 15-17-19-21 step-by-step over the sets of multiple contacts 14r-16182O of the difierent lines, ;he contacts 18 of su'ch lines as are not calling lines, being grounded atthe normal contacts of the lower armatures of the line relays 2. Thus, successive locking circuits are established for relay 22 holding it on ergized, but as soon as wiper 19 engages a contact 18 of the calling line, thatof A, said contact is then ungrounded because re lay 2 of that line is operated, circuit through relay 22 is opened and all its armature's retracted, armatures 23' and 28 closing the circuits of the talking conductors, of the trunk circuit, while armature 24: prevents further operation of magnet M, leaving wipers 15-l7.19-21 engaging respectively contacts l-l--16-18-20 of the calling line, and armature 27 allows relay 38 to e deenergized. Relay 22 thus acts as a test relay in establishing connection with line L"-L' as a'calling line.

With the first actuation of magnet M, the oil-normal switch springs ON, ON, ON, (.).N and (1N were simultaneously shifted to their alternate positionsthe shifting of ().N completing circuit from ground through conductor 57, contact 13, wiper 11 of the master-switch, relay 7 to battery. The relay 7 attracts its armature, completing circuit through magnet 8 which, owing to the interrupter controlled by its armature, is successively ener ized and deener gized as long as relay 7 iolds its armature attracted, stepping wipers 10-11 over contacts 12-13 ofthe different switches C. Relay 7 continues ener ized until-wiper 11 reaches a contact 13 of a switch C which is at normal, as it then forthe first time fails to lind anungrounded conductor 57 -since the coutactsQN' of all busy switches are shifted' When wipers 10-11 do reach contacts iii-13 of an idle switch,relay 7 becomes dci nergized preventing further operation of magnet S and the wipers remain in engaging the contacts of the said idle switch.

As soon as relay 22 is deenergized, circuit is comp eteii from battery B through whose attracted armatures: extend limbs L and L to-the trunk conductors, and open the circuit 'througlrline'relay 2 whose armatures no'uwfall ack, the lower armature causing relay 6 to become deiinergized unless another substation of-the group has its receiver removed by-a calling subscriber when contact 2" or 2 will be. ounded operation of the respective me relay 2. The

retraction of the lower armature of relay 2 also places ground upon multiple contact 18 of the line rendering' it again unselectable by any switch C operating as a line selector. It will be-observed'that relay 6, after relay 2 has once operated,,continues energized as long as the said relayg2 does, while wipers 10-41 start to seelccontacts 12 13 of an idle switch C as soon as the one started has closed its contact O.N.' To prevent an untoward starting of thisother line selector, I provide the relay 9- connected from battery to conductor 58 having taps ending in contacts 4.545-45 etc., one for each relay 22 of the difl'ere'nt switches 0. Thus, as long as any relay 22 continues energized, a circuit will be closed from. ground through its armature 26 to contact 45 45', etc, through by the relay 9 to battery, which relay by attracting its armature, holds the starting circuit of wiper lO-open as longjas a switch C is in operation. .Thus a second switch cannot be started by master-switch K ns long as one switch C 1s m operation. ,It will be remembored that relay 22 allowsits armatures to fall back to cause theenergization of relay 3 which deenergizes inturn relays2 and 6. lnnsn'ulch as current may be interrupted through relay 9 at contact 45 a fraction of a second before current is interrupted through relay 6, the-relay 9 is preferably so constructed as to release its armature slowly after current is interrupted therethrough to insure the deenergization of relay 6 before the armature of relay}? closes its back contact. Of course, if another subscriber has removed his receiver, as a calling subscriber, relay 6 will be held operated, and upon the retraction of the armature of relay 9, a sec- .ond switch 0 will be'sta rted as a line selector. A copper shell may be placed about When the operator answers the call by im sert-ing the answering plug G of her cord circuit E into the ans'werin ,j ckofthe trunk line whose signal 50 is displayed, contacts 59 and 60 engage springs 53 spectively, whileucontact 61 crosses thimbles 51 and 52. The plugs of the cord, circuit are preferably so constructed. that when being inserted into ,a'; springgack such as that shown at D, the-contacts t endgQLdonot ator inserts the calling plug inthe jack of line F. Current then flows from battery B through relay 66,- lcvers 72-78, contact 81-89, relay 87 to ground, energizing both relays and putting a busy potential on contact 83. Relay 87 attracts its arinatures and the 0 erator depresses levers 77.and 78 cansing t ie projection'cf ringing current from generator 79 over the called line through and 54 reengage the thimbles 52 and 51, in order that may not be operated before battery has been applied to spring 54. This may be effected; by making contacts 60 and 81 slightly smaller, asshowmthan the bushings of insulatingmaterial on each side of them. It is immaterial whether the 0pegator inserts the plug before or after the calling line has been selected. Upon the insertion of the plug G in the answering jack at D, circuit is completed from battery B through contact fi l fiil, relay 46 to ground,

energizing relay lfilwhich attracts its arma- -'ture to engage its alternate contact. Relay no click results 47 is thereby denergized and lamp, 50 goes out. Current then through relay 63,contact '54, Larmature of relay 46, limb L, relay34, armatureBS, contact l'T16, relay 3 togroun'th'alportion' also flowing over limb Lihook lever 1 limb L, contact let--15, armature 23, limb L,

flows from battery B contact 53 439, relay 62 to ground- Relay 5 62 is energized and attracts its armature to" prevent the display of signal 64 at this time.

The shiftingof current through relays '34 and 3 at the'urinaturc of relayfi occurring on the insertion of the answering plug, is accomplished quickly 3, if already energized by the selection of the calling line before insertion of the answering plug, hold their armaturesattracted.

so that relays 34. and,

The operator liow depresses levers 69 and 70 01 her listening ley, learns the number of the subscriber wanted. assumed to be F,

and touches tip of the calling plug .to

sleeve 83 of a multiple jack of the line of.

F. If the line is busy, contact 83.\rill be of a potential other than ground and-current will flow through tip S0, levcrs'77-,-71, armature 67. test relay 68 to ground, and the relay will lie energized to" cause a-click in the operator's receiver notifying :her that the line is busy. In such case she will'so advise subscriber A andby withdrawing the answering] plug, restorc switch C as hereafter clest zribed. l't'zhouzever, tinn tus-ted line be'ir'llc. mutant 83 will of tho potential ofgrouu'll q n of relayis:

., and the operspring ON. release magnetRM' to battery.- Magnet RM attracts its armatures locking condenserand call bell returning, through lever 78,.through battery 13 to ground. The operator then restoresthe ringin key le vers. Signal 88 is at this time i'splayed, but as soon as the called subscriber removes his receiver, circuit is closed from ground through relay 65, armature 67, (attracted when lever 7 8 was restored) through levers 7.1 77, contact 81-8 attracted armature of relay 8?, through ransmitter, receiver and-hook lever at the substation, returning through the lower attracted armature of relay 87, contact89181 to battery through relay 66. Relay 65 therefore attracts its ormature to open circuit through lamp 88 Wliosegoing out notifies the operator'that the call has been answered; Subscribers A- and F are now in conversation,the talking circuit being "traced by the heavily marked conductors, talking current being supplied to the transmitter of subscriber A through the windings of relays 63 and 62 and to' the transmitter of si'ib'scriber F, through relays 65 and 66. \Vhen at the conclusion of conversation subscribers A and F replace tl1e1r.rece1vers,

the'shiftings of the respective hook' levers' open the circuits of relays 62 a nd 65, which are denergizedcallowing their armatures-to fall back-closing circuits through lamps 64. I and 88.; The operator in response to thewithdraws theanswering plug G "from the spring jack of the trunk. line. The openings of contacts [ilk-54 and 61.52 cause relays l6 and 3' to release their armatures, the I GlIQ -lG', being so adjusted as to allow relay 3 to (leiinergize and close circuit. through magnet RM before normal contact of said relay 4'6is'ag'ain closed. Relay 34 is rendered sluggish in the release of its arma-.

turefw hi'ch may be effected for instance by a copper shellahout its-core as shown. Ar-

mature 5 of. relay 3 therefore engages its normal contact before armature 36 ofmelay 34 leaves its frontcontact, "and circuit if-rclosed from ground through retracted ur mature 5, contact 2021, armature 36and its fIUDtCOntILGt, shifted otfmm'mal switch,

itself frmu grounded armature spring 44,

spring ON to battery, r=..n1:'1:uing energized until the switch reaches normal when spring UN and the other elf-normal s rings are restored to normal. Arlnatures 4- 13 also close circuit from ground through relay 38 to battery B holding said relay energized during the release. The attracted right armature of magnet RM closes circuit from ground at the shifted cit-normal spring ON through relay 22 to battery, in order that relay 2), be energized and wipers 15 and 17 hence be on open circuit during the release. When the switch wipers are restored to normal, the oll'-n'ormal springs are shifted back to the positions shown, ON removing ground from contact 13, rendering the switch (I selectable by the master-snitch, UN and ON" open circuits to ground from battery through relay 22 causing its det ncn gization. the armatures of relay 3i bein at this time retracted; the shifting of 6N also dei nergizes relay 29, while spring ON doi-"nergizes magnet RM and its armatures ll amt-l3 are retracted to open circuit through relay 338, and the' selective switrh U is at normal.

Let it be assumed that subscriber F desires his line connected with that of subscriber A. He removes his receiver, closing circuit from battery B through relay .85, lower armature of relay 87, through hook-lever 1, receiver and transmitter at the substation, returning to ground over the upper armature of relay 8?: relay 85 is energized to display signal 86, and the operator responds by inserting the answering plug G into thc answering jack of the line, closing contacts 5984, (Kl-89 and (i1'-83. Current then flows from battery 13, through relay 63, contact (KL-89, through cut off relay S7 to ground, energizing relays (i3 and 87, the attracted armature of the latter extending the circuits of the line F to the spring jack contacts. Relay 62'is thereupon energized by current flowing from ground, through contact 59-84, over the line of F, returning through the attracted lower armature of relay 87, contact 89-430, relay 63 to battery; The energization of relay 62 causes it to attract its armature to prevent the display .of supervisory signal 64. The operator now throws over levers 69 and 70 of her listen ing he and a'scertains the number of the subscri r wanted (assumed to be A). She thereupon tests the multiple springjdcks shown at D of the trunk lines assigned tothe group of subscribers among which A is included. The test contacts 51 of bu sy trunks will be connected to battery B by armature 48, as before described, or to battery B at a cord circuit, if connection has already been made to a multiple of the spring-jack tested, In such cases, test r'eley- 68 will be'operated in a manner "similar to that before described. As soon,,however,- as the operator tests I springjgck of an idle trunk, now assumed to be that shown at C, itstest contact contact.82-52 completes circuit from but- 4 tery B through relay in to ground, operating the said relay, which attracts its armature to connect contact spring 54: to line limb L, cutting olf relay 4?. The operator now throws over levers T1 andT'Z to connect her calling device 74, common to the position, with contacts 80 and 81 of the calling plug. Lover 72 when shifted in either direction closes its circuit to the opposed contact before it leaves the contact from which it is being shifted, and this is also true of lever ,78 of the ringing key. This arrangement is to maintain a connection of battery 13 to contact 81 of the calling plug so that relays zi-l and 3 cannot become dei nergized while the levers are being shifted, after they are once operated as hereafter described. It should be noted that the operator has, by testing the trunk jacks of a particular group of trunks and connecting with an idle one, already selected anidle trunk leading to a limited group of subscribers lines, among which. that of the ealled-for subscriber is included. She now turns dial H in the direction indicated by the arrow until a numher of teeth corresponding to the number of subscriber A in the group, plus one, have passed to the right of spring 75. In'thc meantime, the tooth shown in Fig. 2 at the right of spring 76 will hare passed oier the top thereof so that, with the return of the dial to normal, it will momentarily open contact 76. The operator now releases din] 74 and it is turned by its associated spring in the opposite direction, its teeth, causing spring 75 to make and break contact with its associated spring a number; of times, corresponding to the number of teeth passed to the right of spring 75. thus transmitted flows from battery 13 through spring 7 5, levers 71 and 77, contact -53, over limb L of the trunk circuit through back contact of armature 35 and said armature, through relay '37 to ground, energizing the said relay; The said relay therenpon attracts its arinature's, armature 37" completing a. circuit from ground, through its, alternate contact, relay 29. to battery,

tact of said armature 33, whereupon current flows from batteryB, throu h the already attracted armaturcfi'f'of re y. 37, magnet The. first impulse iii oil-normal spring OZN attracted arniqture 31, relay 22 to battery,operating-relay 22. "Armatures 23 and 28 disconnetjiwipers'lli and 17 from battery and groundrespec'- tive ly; armature '26 completes circuit through relay 9, opening the starting con duotor of the muster-switch K; while armature 27 completes .circuitv froln ground -tl1rm1glrreluy 38, over limb L of the trunk circuit to battery at the cord circuit, in order that-relay 38 may beenergized to disconnect the winding 'of,test relay 39 from {armature 28-hefore Wiper 17 is brought to engage a contact forming a terminal of a line. With this first step of the switch, off-normal switch spring O.N is shifted to operate relziy 7 to cause wipers 10 and 11 to move on to'engage and rest upon contacts,terminals ofun idle switch C.

The provision of a grounded contact,,en- 'gaged by wiper 11) on its first step, isfor 30: the purpose of insuring time for the operation of relay 22 to disconnect theline wipers, r and for the operi tionof relay 38 t 0 discon' nect the test relay 39 Wllellgtht} switchis used as a connector, before the linewipers engage the terminals of theifirst line. Said Qeontnct is grounded to cause the swvitchto pass over it when operating as a lineselector. g

The succeeding impulses, transmitted by 40 culling device 7st in its returntogntn inohpass through relay 3,7, which 1 ttmc tsnndj retracts its srmatui'es, armature li'l cuusing n correspondm number of aotuat ons of magnet 5 around to engage the contacts of the lines of the group-the last impulse of course plucinp; them in engagement with contacts ,l r.-16*.1'8- -20 ot'etbe line Wanted. Immediately,following the transmission ofthe lust impulse, the tooth of calling device 74 "opens contain-t7?) for u j moment and then allows-it to close. r'llheophning of the said 'cont'uot disconnects battery from lever 72, contact 81 and sp'ri'n;- 54, causing nmmentary 5 del nergization?of relay 38 which was held energized during,"the'tramsmission of the se-' lecting impulses. 'lhenrmuture of the'said rela y is retracted midtlie windings of polarf :ized relay 39 are thereby momentarily con- 1 nected to attractedfin-mature 28 niid to line wiper 17. Let, it,be assumed! firstthnt: the

some potential as ground, and current will through test reluy39, retracted armnture of relay 38, armature 28, contact 17 16,

throughrelny Ste; ground, f This current is"- in a direction to tilt the armature of polarized relay 39 toth'e'right, which closes circuit from ground through the armature, to Contact 41, through relay 4:2 to battery; the said relny etfinttrncts its armature to open circuitthrough relay whose arlnutures fall back, Relay 42 is preferably rendered slow to release its nrmnture after it is once attracted, as for instance by "a copper shell ubout' its core, so that contact 76 will be closed and a circuit completed from battery B through said contact, levers 72 end 78, contact 8154, relayfiat', retrncted arn'iature of relay- 22, contact 17-46, cut-oil relay to ground, before relay 42re1euses its arms: ture. Hence relay 31 is operated and, by

the nttractiou'of its let'tlmnd' armature 'to disengage its normal contact, prevents relay 22 from again becoming energized when relay 42 releases its armature. and 3 are now both energized; armuturelfi closed its contact in lhr circuit of release magnet BM rxtei'uliug to wiper 21 while armature 5 of relay 3 opened contact in the Same circuit. lm nturc' 'of' relay Bl opens the circuit of relay to prevent its, being again operated when, as hereafter described, the called subscriber establishes a flow of current over his linelimbs, Tbefop- 'erntor now'restores lei ers 71 72 1ndd'c presses her listening key lei'ershfi and and. inasmuch as off-normal switch spring ON 1s shifted. disengaging its contact, she

hears no signal 't'rom the interrupter l.

' 'yl hus, knowing that the culled line'jis; idle,

icalledline is an idle line. In snjclr'case, the... i contact 16 engaged by wiper 17 will be ut the she depresses lever "relny 66, attracting its armature s I thedipl-ny of signallatnp;8 8 whie temams Relays 3i over limb TL of the trunk v circuit, uriniituife 1 23, contact lit -'14, attracted upper hrmature M. which steps .wiprrs 15,-17--l9,21

of relay 3, 1i'ne limb Lfl through the condenser, hell and hook-lever ,ut tbetsubstution, returning oi'e'r limb L'flloiver attracted armature of relay 3to ground through relay 3, the current ulso retilrniug' diver the talking conductor illustnited hyt the heavy line, through lelrer 78 and bat-t'erl 'li toground. The operator then releases levers ,77 und 78 which return tonomrial. L78 inlits return keeping battery continually on contact 31 as-hefn-re described, andTr elay 66 is connected in circuit with "jrelays; 3Q end 3,"s ziid mus displayed until'the celled jsuliscriberfrernovinghis receiverim response to the "signal, completes st circuit" from-ground three h relay 65, nttraotednfmeturc levers, t1 and 7 7, contact 8H3, armature ,28, e'ontnet 15-14,'over"1i nb In, through triinsmitter, receiver and hook l ever at thesuhstution,re; turning throughflcontact 16 17, armature.

. reaches normal. magnets 22 28, relay 34, contact 5&81, relay 66 to bat-v tery, which flow energizes relay 65 and causes it to attract its armature to put/out the lamp 88, notiiying the o orator that the subscriber has answered'.' Su s'cribers A and F are now in conversation, the talking ch? cuit being traced by the heavily marked condoctors and battery being supplied to the line of subscriber F, through the'windings of relays 62 and 63, and to the line of,A through the windings of relays (i5 and 66. When the subscribers have finished their conversation,'theyreplace their receivers, causing the'display of the two signal lam s 64 and 88, whereupon the operator wit draws the plugs of the cord circuit from the spring'jack, restoring the line circuit of F to normal and also restoring switch C to normal in a manner similar to that hcrein before described.

Let it now be assumed that a selector switch has already connected to the line of A at the time relay 38 was deenergizcd to connect the test relay 39 with wiper 17. In such case, current will be flowing to ground through relay 3 from battery 15. through relay 47. or from battery B at the cord circuit if connection exists. Owing to die resistance of relay 3 and the other instrnmentalities in the circuit, there will then he a potential at contact 16 of the line of A already engaged by another switch (3 and its multiples, now engaged bythe switch making the test, greater than the potential at the intermediate tap of battery B.

inder these circumstances, a flow of current will take place, when relay 38 is deenergized, from contact 16, through wiper 17, attracted armature 28, winding of polarized relay 39, to the intermediate tap of battery 13 and to ground. This current flow, being /in the reverse direction from that occurringwhcn the called line was idle, tilts the armature of relay 39 to the left to engage contact 40, whereupon current flows from the grounded armature, through contact l0, shifted ofbnormal switch spring UN". release magnet RM to battery B. Magnet RM thereupon locks itself as before described, continuing locked until the switch Its energization causes and 38 to be energizedas before described; and when the switch reaches normal, all apparatus is restored as before described. The operator, before throwing over her rin ing-key levers, depresses her listening-key evcrs as before described and then receives from interrupter I thc busy signal, which passes through the now closed oilnormal switch contact ON", its associated condense over limb L of the trunk circuit, contact lid-81, through relay 66 to battery, charging and discharging the condenser in the sleeve strand of the cor and causing the customary buzz in the opringing-key, as the calling su crators receiver.. The signal will also be. transmitted to the calling subscriber and the operator now restores her listening-key and withdraws the lugs without operating her ringin -key. he relay 37 may be so orrange asnot to be responsive to the alternating current generator, used for ringing, sulliciently to fully attract its armature, in which case it will not be necessary for the operator to listen in before operating-her scriber will (on receiving the busy signal from interlace the signal which will indicate to rupter I, if the called line be busy) re his receiver to cause the display 0 supervisor the operator that she should take down the connection.

The operations taking place .when 'a subscriber, belonging to a group such as that to which A belongs, is to be connected to another'subscriber of the same group or another group, will be understood fromthe description already given and a detailed description, which would consist merely of a repetition of one-half ofthe operations performed. in putting through the connection already described, will not be given.

I show at O.R what may be termed an over-run switch, its contact bein nor mally open as shown. When the switch C has been in any way 0 rated so far that its wipers ass beyond t e last contacts contained in t eir banks, the contact of switch OR is automatically closed to complete ci'rcuit through the release magnet RM when the switch will be restored to normal, deenergizing relay 9 to render master-switch K effective under controlof calling sub scribers.

It will be understood that the batteries shown at B and B may be a single ex change source of current, while that shown at B, supplying current to switches at a distance from the exchange, may preferably be a separate battery. 1

Referring to the mechanical drawings in Figs. 3 and 4 respectively, top and side views of the master switch. the terminals 10 and 11 shown at K in Fig. 1 are prcferably common strips, as indicated in Figs. 3 and 4, extending around under their respective sets of contacts 12 and 13, the wipers 10 and 11 having in themselves no circuit connections, but being arranged, when moved, to merely cross the common strips 10 and 11 to successive contacts 12 and 13 respectively.- The contacts and common strips are" ar ranged in a curved bank as shown, the wipers 10% and 11 being fastened to a suitably supported rotary shaft 92 to which is also fastened the circular rack .90, adapted to be engaged by the armature-driven pawl of magnet 8, and to be turned by successive thrusts of said pawl to more theshuft and wipers 1Q. and 11' one step for each thmst.

3 in Fig. '1 isshown in Figs. 5 and :6. 'Mul I first, twenty-five lines of I stepior-each ing pawl 95 is held by itsv spring against same numbers being co ON which by its tension a The parts of wipers 10' and 11* posed at suchnnglcs that one contact 11 and one contact 12 are always engaged by them. The, movement of the wipers'being always in thecsame direction, no restoring mechanism for magnets includes spring 91 andits con tact, sand spring beingactuated to free its contact and open the magnets circuit, by an associated arm fastened to the. armature.

A prcferred form of mechanism foruse in connectionwith the circuit shown at G tiplc line contact sets, comprising each con tacts 14, 16,18 and 20, are shown for: fifty lines, disposed-in two curved rowsof twentyfive contact sets each, the contact sets of-the the fifty "being superposed "upon those of the last twentyfive' lines, the permanently grounded contact 93 of Fig. 1 being shown at theicft-of I the first contacts 14, 16, etc.,

in Fig. 5. The curved rows of contacts are rigidly fastened to main frame 102, and two sets of wipers 15, 17, (19' and 21 (those having the ccted together) are provided at the axis of curvature 'fastoned tothe rotary shaft 99, to which is also fastened one end of restoring spring 101 against Whoso'tension the wipers and shaft 99; are turned. The-two sets of wipers are ,set'at such anglethat "when the set, whose wiper 15 is shown adjacent to contact 93, has been brought around so that it is: about to leave itsbank' of contacts 14,16, etc., the other set of wipers will be in a position such nsto be about toen'gage the'first contact set of its bank. The circ'iilar, i a'ck' 96 'is fastened tosh'aft 99 and is turned, carrying the shaft and wipers around," by armature driven pawl 94 of magnet M, moving the wipers a thrust of, said pawl. Retainrack I96; to prevent back movement durin operation of the switch. thrustof'pawl 94', the stud 98, mounted on rack 96, releases off-normal 'switch spring moves to disengage its contacnand also m'ovesout of supporting relation with stud2104, whereon springs ON,ON, ON. and ON move to engag'eftheir respective contacts.

c ben gn or, upon ha Whgll i rgized, its

are a dis is required. The circuit-breaker The arm 105 fastened controlled at the station to automatically connect Withkafthe first If the switch operates so far that the wipers pass rotatably mounted I l armature rotates pawl 95 to free rack 96, andthe spring 101 (Fig. 6) is effective to rotate the shaft, carrying the ,rack and wipers, back to normal, stud '98 then engaging spring ON and shifting it back, whereto rack 96, normally engagingstud 1B3, moves away from the stud when the switch is operated; and on the restoration of the-switch, serves, by again engaging stud 103, to stop the shaft, rack and wipers as soon as they reach normal.

;I claim as my invention 1. Atelephone system including telephone circuits, link-circuits for interconnecting said telephone circuits, electrically actuated step by step selective switches therefor and for common use of said telephone circuits, and means for employing said switches interchangeably to connect with calling 'or called telephone circuits.

2. A telephone, system including a telephone circuit, an electrically actuated step by step selective switch, a second telephone circuit, stations for said circuits, mechanism ofthe first circuit said switch with said first circuit when a calling circuit, and mechanism at the station of the second circuit for automatically; controlling said switch to connect it with said first circuit as it called circuit.

3. A telephone system including a tele; phone line,' an electrically actuated step by stepselcctive switch adapted on initiation ofa call at the station" of said line to automatically' select and connect with said line,

trolled ther'over' for changingthe mechanism of-s'a'id switch to render it operable, responsive to currents over said second line, .to select and connect with said first a called line, i

4;. A tclephone'system including a telephone line, multiple contacts for said line, electrically actuated step by step selective switches, and means, for operating said switches for connecting to said contacts to extend the circuit of saidline as either a, calling or 0. called line. I

5. A telephone systemincludingtelephone lines, link-circuits for use \in connecting said liI,1'es, -an d' electrically actuated step by :step switchingmechanisms for said circuits for interchangeably connecting said circuits directly to said lines whether as calling-or called lines.

(if A telephone system including a seleccalling or called lines, a test "relay for said switch-adaptedeto test said lines as callinglines and a second test relay for said switch adapted to test said lines as called lines.

' 7. "A, telephone" system including-telephone lines, a link-circuit, a selective swltch atom:

by all the off-normal springs'are restored.

line as l nd of said link-circuit for connecting said' link-circuit with said lines individually, and means for controllin the selective 0 tion of said switch indi' erently 0v 1- said circuit, and said lines, Whereb aid llnke circuit is rendered capable of use-for both incoming and outgoing calls of said lines.

8. A telephone 5 stem including a "telephone line, electrically actuated step by step selective switches at an excbsngennd means for selectively operating said switch indit ferently for incoming and outgoing calls of ing the normal electrical condition of said last-mentioned terminal, and means responsive to such changed condition to cause an alteration of the normal electricalcondition of said multiple terminals to render them busy.

11. A telephone system including 'a tele phone line a link circuit, multiple terminsls at one end of said link circuit and a n'onmultiple terminal at the other end of said link circuit, electromagnetic means automatically controlled for advancing said nonmultiple terminal into connection' with said line when calling, means for alter-in the normal electrics] condition of mu tiple terminals responsive to such automatic control, and means for also dimctively'operat ing said non-multiple terminal for connect ing to said line as 9, called line.

12. A telephone system including an electricsllty adjustable selective switch, circuits capab e of selection thereby, two controlling points for operatin said switch, an operatmg magnet for sai switch, a relay "for controlling said magnet operable from one of said points, a second relay for controlli said magnet operable from the other of sai points, and means eifective on operation of either relay toremove said magnet-from control of the other relay. i

13. A telephone system including electrically adjustable selective mechanism, a. pair of relays each odap for independently causing the operation of said mechanism, and means for .operatinghdne of said relays to temporarily render t c said other relay inelfsctive to control said mechamsm.

14. A telephon'e'syst m including a telephone line, a link-circuit, an electrically actuated step by stepselective switch for said 'circuit, automatic means for operatiu said switch to select said line, and means or directively operating said switch to connect with and line.

15. A telephone system includin m telephone line, an electrically actua etc by step selective switch, means controlled mm the stution of said line for causing s'aid switch to automatically select said line, another telephone line, and means controlled at a station of said other line for directively operating said switch to connect with said first line:

16. A telephone system including atele phone line, conflicts individualthereto, ele'ctromagneticall controlled step by switching mec shim-adapted to connect d1 rectly with said contacts, automatic meansfor 'adjustiug said switching mechanism to action with said line as a calling line,

and electromagnetic means for directivelv ddj said swi mechanism to coni''llh i? l 1. opens incu' agrou of telephone lines, an electrically actuated step by step selective switch at the exchange, automatic means for ca an independent p ve movement of said switch to cause it to ick out the calling line, and mechanism for 'rectivel lect the call line. I

18. A telephone system including a grou of telephone lines having multiple termini contacts at the exchange, olectroma etically adjustable switchingrnechanism a pted to connect with said contacts, mechanism 'for automatically adjust laid switchi mechanisnrto connect wi any ca 1 said-group, said ad'ustment omstituting the first extension of a no as a calling line, andmechanism for causing said switch when idle to select a particular one oi said lines, said selection constituting the finel extension of a line as a call' able step by ate iaelectiv'e switches for co|nmon use of mi lines and ads ted each to be indifl'erentl employed as o ine selector to select the ca ling line or as a connector to select the called line.

20. The combination with a telephone line arm electrically controlled step by step selective switch ads ted to automaticall select said line as Ice lin line, and m anism for rendering said which unavailable thereopei-ating said i switch 'to seine of thereby, moons fol-causing an minals, and means for causing a directively controlled movement of said switch engaging successively said same terminals.

22.'A telephone system including a selective su itch, telephone lines having multiple contacts for engagement by said switch, almagnet for adjusting "saidswitch,

magnet insensitive to the electrical condigroup.

jtions of the-contacts of said lines, means for transmitting a pro-determined number of current impulses to said second relay to tending the circuitof saiclqlinehpast said selecting switch to another switch of said plurality; and mechanism for electrically adJuSting said last mcntio'nedswitch "inconnection with a particular called line of said 24. A telephone system including group of telephoneflines,

switcliescommon to said lineseach adapted for automatic and directiye; operation in com neeting with said lines! mechanism elfective on initiation of a call over a line to'auto-f matically start one of said switches and cause it to select the .call'ing' line, means for isolating said selecting switch, link-circuits for'cxtendingthe circuit of the cal'ling line )ast said selcctin switch to anotherswitch' of said'plurality, mechanism for electrically adjustingfsuid last mentioned switch to so lect a particular called line of saidagroup, and means for isolating said last-mentioned switch. l i

25. A telephone system inoludinga plurality of groups of telephone lines; a plurality of selective switches for each ,of said groups, of "telephone linc's' each, switch adapted. for automatic and directive opera tron to connect with the lines of its group, means controlled at the substation of a line. to cause an idle switch of the plurality forgroup to nutomaticallv select the linens y a calling line. link-circuits for extending line past said switch: to an idle one of'said selectin'g switches for the same or am other group of lines and -meuns for electricallyadjusting said Q-lastmentioned switch to select a particular called the fhe'circuit of the calling line of the group to which it belongs.-

2h.- A'te'lephone' system including a plurality of telephone lines, a calling line sea relay forcontrolling said magnet sensitive to the electrical conditions of the contacts of said lines, a'second relay for controlling said a plurality of selecting line.

lective switch common to said lines, means for starting said switch controllable at any calling substation of said telephone lines, a

signal displayed \vhen'said switch is started,-

a circuit for extending the connection of said cuit for efi'acing said signah 37: A telephone system including a plurality of telephone lines, a selcctive s witch commontosaid lines, mechanismactuated on initiation of a call at a substation of a. line for starting said switch, multiple test ter- .70 switch, and means controlled fromfsaidci'rminals for saidswitch', and means for alteri ingthe normal. electrical character of said terminals to.' re nder them busy, effective when said switch is started from normal.

28'. A telephone system including a. group of telephone lines, a plurality of] selective switches common toss-id lines each adapted for automaticanddirective operation in estabhsh'ing connections with said 11nes,'means cfi'ective oninitiation of a ca ll over a line to cause one of SfllCl sw tchesto automatically select thecalli-ng line, multiple terminals {for said selective switch, means for changing the.

link circuits for extending the circuit of the normal electrical characterofjsaid terminals j normal electrical condition of said terminals. 1 when said switch 1s m use-to render them busy,

to 'renderthem busy, eiiective whenfsaidline" for. electrically adjusting said last mentione'd switch to select aparticularjculled line.

15 extended to ,said switch. and mechanism 29. telephone-system including agroiqi oftelephone lines,"selectivdsiyltches for con-" necting 'Witlrsaid lines, meanstefiective on initiation ofa call at a substation 'ofa line to cause an idle one of said switches to automatically select .the' calling line, link;

circuits for extendingthe circuit of the-calling line heyond;s a'idswitch to anotheridle one of said"switches, and imeansfonelecA .110 tricallyadjlustingisaid last-mentioned switch I to cdnnection witf a particular calledline;

calling line past's'aid switch to'another switch of saidfgroup, multiple terminals of I said otherrswitch, means-for changing the 30. Ajtelcphone systeni'including a plutrunk circuits for said switches extending to, the exchange,-a for-each trunkat" the exchange, meansieifective on initiation of acall over a line-to causeian idle. oneofjsaid selective switches to automatically, connect its trunk to said line and display its signal,

board, "apparatus included therein for .extending the circuit of a trunk .vvhosesienal is displayed to'anridle oneof sa d switches,

-o erators connectiiw means at said -switch-' 1 ralitv of telephone linea a less plurality o'f" selective s'i'i it'ches common to saidf lines,

and mechanism controlled bvthe operator- 1 for electrically ad usting said last-mentioned switchto' connect w t pa ti u ar q l d Atelephone system'including a. 5111 1'3? 'lineanddirectivelyinresponse -Pr vided with a the'restadap phone ciated with 'rality of-telephone lines, sclectiye switches select the calling lint, a telephone switchboard, and o to connecting 'means to electrically cause adjustment of an idle one of. said switches to com pact with any one of laid lines as a called 32. A tele hone systemj inclu a group oi tele bon lines, selective swi com- Znhongtl'eto, to be inter; ange'a yemp oy or incoming oron E333 calls of said-lines, a tele hone switch for'saidesand tiple terminals therefor at said hoard.) operators connective means for a switch em loyed for an outgomg'call tu a switch capo ed foran incontingcall.

33. A ep nesysteminclu' agronp of tele hone lines, selective swi es comhgeabl l ed i to be y emp oy' or incoming er on going calla ofsaid lines, a tele hme switch.-

signals for said swit and multiple terminals therefor at said board, operators connective means or connecting a switch employed for an 'outgnngcall to a switch employed for an incoming call, and means controlled by the operator for resysi ni "tel ep one com nsmga eline, a link-circuit, a litch having contacts for connecting saidline and link circuit, and means for establishing such connection automatically in solely to a control eaercised' over said e as t; callmg' a controalsexzrcifisled l:vel' said linkil-lcdircuit' in ep one system ndmg a e lsilurah't'y of multiple terminalsattheex an ,eachterunnal including a plurality 0 switch contacts, one serving as a test contact for-tbs line as a called line, and another as a test contact for the line as a calling line, wipers movable over said contacts, and mechanism assosaidwi and operableindiiierent ways m H; to the condition of the encountered testcontacts. 80. A telephonesystmnincluding a subscribers line, a terminal for said line at the exchange including a pair f test contacts, one serving to protect aai hnedrom 1ntrusionwhentestedasacalledline,the othertoprotcctsaid 'ewhenteatedasa eallinglinqa' eunitaryswitchatructureha' move etestmemberstorcon- 'nectien wi mid contads respectivel and ted devices connected with said sw' sensitive to the electrical conditions of said test contacts.

87. A telephone system including a telephonslinaatermmaltheretorattheesmemes change includin a of to contacts, a selective switch or lmployaaent in the circuit of said line'as either a calling or a ,called line, two ted for can switch adapted to be with said test can test devices for each said member, an means for employing the device of one member or the other according as the terminal is tested Etch as the terminal of a called or calling 88. A telephone stem includin a selective switch, multip 0 terminals in uded in said switch, each terminal including a pair of test contacts, one test contact of each terminal being normally selectable and the other unselectable by said switch, means for rendering the normall selectable contact of a terminal unselectab e by said switch, and

means for rendering-the normall unselectsblecvitlontact of a terminal eel is by said swi ,89. A telephone syiaem including adzeileg u -tive switch, multiple terminals said switch, each terminal including a'pair of test contacts, one test contact of each terminal being normally selectable and the other unselectable by said switch, means for rendering the normall selectable contact of a terminal unselecta is by mid switch, means for rendering the normally unselectable contact of a terminal selects le said switch, and means effective on ection trade to render both said contacts unselecta e. c

40. A tale hone system including a pinrality of ective switches, termmals included in each said switch and multipled from switch to switch a of ted contacts including in each and terminal, one being normally selectable and the other unselectable, test means for said switches sensitive to the electrical conditions of said normal selectable contacts, other M means or said switches sensitive to the electrical conditions of said nonnally unselectahle contacts, means for rendering the normally unselectable contacts selectable, and means for rend the normally selectable contacts unselectab 41. A tele hone system rality of scective in cluded in eachsaid switch and multipled from switch to switch, a pair of test contacts included in each-sa1d terminal, one beinf normally selectableand the other, unse ectable, test means for said switches sensitiveto the electrical conditions of said normally selectable other test mean for switches sensitive to the elecconditions of s;id nor-gull 0 contacts, means or ren malty unselectable contacts am: for rendering the tacts unselecta the norof said contacts, of twotest devices for Said I switch, one adapted to be placedin'connec tion with each-contact, and means for determining which of said devices shall ,be operative when a terminal istested.

44. The, combination with a selective switch, includinga multiple terminal having two test contacts individual tQfltfllIlCl means for altering the electrical conditions of said contacts, of two test devicles'for; said switch, oneadapted to be placed in connection with each contact, two circuits for ini-.

tiating travel of said switch, and means for rendering the one or the other of said test devices operative when a-t'erminalis tested according to the circuit employed.

45. In a telephone system, the combination with multiple contacts, of selective switches for selecting. said contacts, a common starting conductor-for initiating travel to,o crate saidcontact to restore'the normal g p mg from S81dW1t0ll to an operators pos of said selective switches, arelay having a switch contact included in said starting conductor, and means for holdm said relay energlzed as long as any selgctive switch is traveling to maintain open said starting conductor.

46. In a telephone system, the combination' with multiple contacts, of selectiveswitches for selecting said contacts, acornmon starting conductor for initiating travel of said selective switches, a relay having a switch contact included in said starting conductor, means for changing the, electrical condition of said starting conductor to'initiate travel of an idle switch, a switch contact included said starting conductor, and a relay energlzed on starting of a switch con ition of said conductor.

47. In, a telephone system, the, combination with multiple contacts of selective switches for selecting said coht monstarting conductor for initiating travel of said selective switches, a relay having a switch contact included in said starting conducto'r, a switch contact included in said starting conductor, a relayenergized on starting of a switch to operate said contact to restore the normal condition of said 'conductor, and means for holding said relay energized during the travel of the switch.

last-mentioned switch.

acts, a com:

for each means effective on the starting and during the travel of a selective switch to hold ener' gized said relay whereby-said conductor is in its normal electrical condition.

49. In a telephone system, the combination' with multiple contacts, of selective switches: for selecting said contacts, adistributer switch for starting said selective switches, contacts of said selective switches at said distributer' switch, means-whereby said distributor switch normally engages a contact of an idle sel'ectiveswitch, a start ing conductor for said 'distributer switch adapted j to be" interchangeably connected" with said contacts, ai-relayforsaid dis- ,tributer switch, a" contact therefor connect- "ed with said conductor, and means etl'ective on the startmg and during the travel of a selective switch tov hold energized said relay whereby said conductor is in its normal electrical condition. y

50. A telephone system incl ding a group of telephone lines, a pluralit switches common to said lines each adapted for automatic and directive operation in connecting with said lines, mechanism effective on initiation of a call over'a line to automatically start one of said switches and cause it to select the calling? inc, 'means for renderin busy'said "selecting switch, linkcircuits' or e'xtendingtlie circuitjofjthe callingline 'ast said selecting switcl'rtoanother switch oi said phniality, mechanism for elec} trically adjusting said last-mentioned-switch to selects particular called .line ."of said group, n'd means for rendering, busy said 51.- A telephone system'includin'g a.- plurality of, telephone lines'n selective switch common to said lines, a. ink-circuit extendtion, a call signal at said position, means iior starting. said switch, means for displaying said signal when said switch is started, and

operator-75 means'for extending the circuit each trunk line adapted for intermittent or step by -step operut1on, a set of conductors group of telephone lines, means v, of selcctinggloo connection with any one of the whereby the removal of the receiver of any telephone of either of said groups of telephone lines shall com lete a circuit through the associated set 0 said conductors and cause any one of the switches of the group of trunk lines associated with the group'of telephone lines in which the operated telephone is included to operate and connect the telephone line of such removed receiver to the trunk line associated with the o e'rated switch, instrumentalities whereby t e central operator may establish communication with the telephone line of the said removedreceiver, and meanswhereby the cen-. tral operator may effect the operation of any switch'of the other group of trunk lines and cause said switch to establishelectrical connection with the line of the telephone with which communication is desired.

53. In a common battery telephone aystem, the combination with a trunk-line and a group of telephone lines, of a telephone line selecting switch for the trunk-line, adapted for intermittent or atep-by-step operation, suitable conductors, means whereby the removal of a telephone receiver shall complete a cirwit through such conductors to cause said switch to connect the telephone line from which the receiver has been removed,

to the trunk line, means whereby the central operator may also etfect the operation of said switch and cause it to establish electrical connection with the line of the telephone with which communication is desired,-

} hone lines and a group of trunk inea; of a ephone line-selecting switch for each trunk line susceptible of making electrical group of telephone lines, a set of conductors for the goup of tele hone lines, means'whereby e removal 0 a receiver of anyone of the telephone lines shall complete a circuit 'throu hthe said conductors to cause any one o the said switches to operate and con nect the telephone line of auchremoved reoeiver with the trunk line associated "is the operated switch, and means wherebye sisv central operator may ettect the o ration of any other switch of said group trunk-line associated therewith and cause said second'switch to establish'electrical b communication between its respective trunk line and the telephone line of said group of lines, with which communication is desired.

55. In a common battery telephone system, the combination with a trunk-line and a group of tele hone lines, ofla telephone line-selecting switch for the trunk-line, suitand means to restore apparatus to normal rough the able conductors, means whereby the removal 66 of a telephone receiver shall complete a circuit through such conductors to cause said switch to connect the telephone line iron which the receiver has been removed to the trunk-line, and means whereby the central 7o operator may also efl'ect the operation of said switch and cause it to establish elec trical connection with the line of the tele; phone with which communication is desired; 56. In a common battery telephone syn;

tern, the combination with a trunk-line and a group of telephone lines, of a telephone line-selecting switch for the trunk-line, suitable ccnductors, means whereby the removal of a telephone receiver shall complete a circuit through such conductors to cause said switch to connect the telephone line from which the receiver has been removed to the trunk line, and means whereby a circuit may also be completed over the trunk line and efl'ect the o ration of said switch and cause it to establish electrical connection with the line of the telephone with which communia cation is desired.

57. A group of telephone lines; a line finder common to said group; a manual telehone switchboard; electrical connections tween said finder and said switchboard; aignalin apparatus at said switchboard controlled t u h said electrical connections; and means whereby the line finderand the signaling apparatus may, through said elec trical connections, become simultaneously active in response to a calling tale hone line.

58. A group of telephone 'nes; a line finder common to and group; a manual telephone switchboard; electrical connections be tween the finder and said switchbpgrd; signalin apparatus at said awitchh,, rd controll thrc h said electrical connections; means whe y the line finder and the signaling apparatus may, through said electrical connections, become simultaneously actire-in response to a calling telephone line no position.

a 59. A telephone system including telephone circuits, link-circuits for interconnecting said telephone circuits, electrically actuated step-by-step selective swiches therefor, and means for employing said switches interchangeably tocpnneet with calling or called telephone circuits. 7

60. Atelephone system including a tale phone line and an electrically actuated step y-step selective ayiteh having contacts indmdual to said has, and means for automatically connecting to aaidcontacts to extendthe circuit of. said line as either a calling or a called line. 126

61. A telephcpe system including telephone lines. a link-circuit for use in connecting and lines, and electrically actuated stcp-by-step switching mechanism foi sold circuit for connecting said circuit directly to said lines whether as ceiling or called lines.

62. A telephone system including a telephone line, an electrically actuated step-bystep selective switch at till exchange, and means fOl selectively operating said switch indifierently for incoming and outgoing calls of said line.

63. A telephone system including a telephone line, a link circuit, an electrically actucted step-by-step selective switch for said circuit, means for operating said switch to automatically select said line, and means for dircctively operating said switch to connect with said line.

64. A telephone system including a telephone line, contacts individuel thereto, electromagnetically controlled stepbystep switching mec anis'm adapted to connect directly with said contacts} mechanism for antomaticully adjustin'g'sind switching mechanism, t0 connectiolt with said line as a celling line,an'd electiomcgnctic incims for di rectively udjusting'seid switching mechanism to connection with said line as it called line.

(55. A telephone system including a group of telephone lines, an electrically actuated stepby-step selective switch at the exchange, means for causing an independent progressive movement of said switch to cause it to pick out the calling line, and mechanism for directively operating said switch to select the called line.

GO. A telephone systemincluding telephone lines and electromagnetically adjustable step-by stcp selective switches adapted each to be indili'erently employed as a line selector to select the calling line or its a con nectar to select the called line.

In witness whereof, I hereunto subscribe my name this 24th day of November, 1906.

LEROY D. KELLOGG.

Witnesses:

Geo. E. Monnnsn, HPG. OLMETEAD. 

